Discrete scheduling-oriented hierarchical timing Petri net deduction simulation and conflict resolution method

Abstract

The invention discloses a discrete scheduling-oriented hierarchical timing Petri net deduction simulation and conflict resolution method. The method comprises the following steps of: realizing hierarchical modeling of a discrete task; specifically, a hierarchical timing Petri net model is composed of a place, transition, a flow relation, place time delay, transition time delay, an identifier and a mapping function, hierarchical modeling of discrete tasks is achieved, a subtask hierarchical timing Petri net and a meta-task hierarchical timing Petri net are included, the former shows operation logic of a composite task on a subtask level, and the other shows operation logic of the composite task on a meta-task level. The latter shows specific execution steps of the composite task at the meta-task level; an execution library in the sub-task level timing Petri net can be mapped into a meta-task timing sub Petri net in the meta-task level through a mapping function; the hierarchical timing Petri net model takes a discrete task scheduling result as input, realizes dynamic conflict resolution of the discrete task scheduling result in a deduction simulation process, and is particularly suitable for simulation of discrete event systems such as intelligent manufacturing tasks, intelligent logistics processes, industrial automation system cooperative control and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of discrete system modeling and simulation, and specifically provides a hierarchical timed Petri net deduction simulation and conflict resolution method for discrete scheduling, which is particularly suitable for the simulation of discrete systems such as intelligent manufacturing task scheduling, intelligent logistics process optimization, and collaborative control of industrial automation systems. Background Art

[0002] As a powerful mathematical tool for describing discrete system states, events, and their interrelationships, Petri nets not only intuitively display system structure and dynamic behavior, but also, due to their unique characteristics, have become an effective means for simulating discrete task scheduling results. In discrete system fields such as intelligent manufacturing task scheduling, intelligent logistics process optimization, and collaborative control of industrial automation systems, Petri net-based discrete task modeling and scheduling result simulation face a series of core challenges:

[0003] First, the traditional Petri net adopts a single-level modeling approach, which makes it difficult to depict the hierarchical structure and parent-child hierarchical relationships of tasks, resulting in significant limitations in revealing the internal mechanism of tasks.

[0004] Second, the traditional Petri net timing mechanism is a single fixed delay, which cannot describe the dynamic dependency of subtask execution time on the parent task state. This ultimately makes it difficult for simulation timing accuracy to meet actual requirements.

[0005] Third, the existing scheduling result simulation and conflict resolution methods are dominated by static temporal logic. These methods rely on static adjustment strategies, fail to fully consider the real-time time attributes of tasks, and cannot achieve dynamic adjustment of scheduling results.

[0006] Although existing technologies have attempted to improve the modeling structure through hierarchical Petri nets, a complete technical solution that integrates hierarchical modeling, dynamic simulation of scheduling results, and conflict resolution has not yet been formed. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a hierarchical timed Petri net deduction simulation and conflict resolution method for discrete scheduling, which can accurately model the structure and timing characteristics of hierarchical discrete tasks and realize dynamic conflict resolution during the deduction and simulation process.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A hierarchical timed Petri net deduction, simulation and conflict resolution method for discrete scheduling includes the following steps:

[0010] Step 1: Construct a hierarchical timed Petri net model

[0011] The hierarchical timed Petri net model is composed of places, transitions, flow relations, place delays, transition delays, identifiers, and mapping functions, and includes a subtask hierarchical timed Petri net model and a metatask hierarchical timed Petri net model; the subtask hierarchical timed Petri net model represents the operation logic of the composite task, and the metatask hierarchical timed Petri net model represents the specific execution steps, and the two are associated through a mapping function R;

[0012] Step 2: Initialize the hierarchical timed Petri net parameters of the scheduling result, including:

[0013] Read the scheduling results of composite tasks, subtasks, and metatasks;

[0014] Initialize the subtask level delay parameters based on the subtask execution duration and start time;

[0015] Initialize meta-task level delay parameters based on meta-task execution duration and offset time;

[0016] Initialize the resource library token value according to the resource load limit;

[0017] Step 3: Execute scheduling result simulation and dynamic conflict resolution, including:

[0018] Calculate the meta-task start time and generate the task list C and time list CST in order from front to back;

[0019] Run the Petri net in chronological order to detect whether the token value of the resource library exceeds the limit;

[0020] If the limit is exceeded, the starting time of the conflicting meta-task is postponed by a resource conflict adjustment step at, and the task list is updated and the deduction is repeated;

[0021] Step 4: Output the discrete task scheduling results after conflict resolution.

[0022] Furthermore, in the step 1, the hierarchical timed Petri net model is composed of 7-tuple LG=<P,T,F,DP,DT,M,R> Formal representation, where:

[0023] P = {PM, PF, PC, PR} is a place set, including the composite task place set PM, the subtask place set PF, the metatask place set PC and the resource place set PR;

[0024] T = {TF, TC} is the transition set, including the subtask transition set TF and the metatask transition set TC;

[0025] F = {FF, FC} is a flow relationship set, including the subtask flow relationship set FF and the meta-task flow relationship set FC;

[0026] DP = {DPF, DPC} is the delay set associated with the library, including the delay set DPF associated with the subtask library and the delay set DPC associated with the metatask library;

[0027] DT = {DTF, DTC} is the set of transition-associated delays, including the set of delays associated with subtask transitions DTF and the set of delays associated with metatask transitions DTC;

[0028] M = {MF, MC} is a set of identifiers, where MF and MC respectively describe the vectors of the number of token values of each resource library in the subtask level and metatask level timed Petri net models at the current moment;

[0029] R represents a mapping function, which is used to map the subtask execution library into a meta-task timed sub-Petri net.

[0030] Furthermore, the subtask hierarchical timed Petri net model is composed of compound task places, subtask places, resource places, subtask transitions, flow relations, and associated delays and place identifiers; the metatask hierarchical timed Petri net model is composed of compound task places, metatask places, resource places, metatask transitions, flow relations, and associated delays and place identifiers.

[0031] Furthermore, the subtask hierarchical timed Petri net model and the metatask hierarchical timed Petri net model are both constructed through four basic Petri nets: sequential, parallel, resource exclusive, and resource competition; among them: the sequential relationship timed Petri net represents the serial execution logic between tasks; the parallel relationship timed Petri net represents the task synchronous execution logic; the resource exclusive relationship timed Petri net represents the exclusive resource logic; and the resource competition relationship timed Petri net represents the resource preemption logic.

[0032] Furthermore, in step 2, the subtask level delay parameter initialization method is:

[0033]

[0034] Where: dp fd (i,j) is the subtask FE i,j Execution place delay of FE i,j .DT is the subtask FE i,j Execution time of dt fs (i,j) is the subtask FE i,j The start transition delay of FE i,j .ST is the subtask FE i,j The start time of execution.

[0035] Furthermore, in step 2, the meta-task level delay parameter initialization method is:

[0036]

[0037] Where: dp cd (i,j,k) is the meta-task c i,j,k The execution place delay of dt ce (i,j,k) is the meta-task c i,j,k End transition delay; c i,j,k .DT is the meta-task c i,j,k Execution time of c i,j,k .Offset is meta-task c i,j,k The execution offset time of subtask k is FE i,j The number of meta-tasks included; n is the total number of meta-tasks included in the subtask.

[0038] Furthermore, in step 3, the resource conflict adjustment step length at is defined as: delaying the start time of the later-executed meta-task to a time that coincides with the end time of the earlier-executed meta-task that caused the resource conflict.

[0039] Furthermore, in step three, the method steps for executing scheduling result simulation and dynamic conflict resolution are as follows:

[0040] 31) Using the hierarchical timed Petri net of the initialized scheduling result, calculate the start execution time of the meta-tasks, and generate the meta-task list C and the meta-task start time list CST in order from front to back;

[0041] 32) Let i = 0, t ―1 =min(CST);

[0042] 33) Determine whether i is less than the length of list C: If so, let t i = CST[i], the hierarchical timed Petri net of the running scheduling result, the running step is t = t i ―t i―1 ; If not, go to step 4;

[0043] 34) Determine whether the token value of the resource library occupied by the meta-task C[i] at the current moment exceeds the load limit: if not, set i=i+1 and execute step 33); if so, delay the start execution time of the meta-task by a resource conflict adjustment step at, update the meta-task list C and the meta-task start time list CST in the order of the meta-task start execution time from front to back, and execute step 32).

[0044] The beneficial effects of the present invention are:

[0045] The present invention is a hierarchical timed Petri net deduction, simulation and conflict resolution method for discrete scheduling, which realizes hierarchical modeling of discrete tasks. Specifically, the hierarchical timed Petri net model is composed of places, transitions, flow relations, place delays, transition delays, identifiers, and mapping functions, which realizes hierarchical modeling of discrete tasks, including subtask level timed Petri nets and metatask level timed Petri nets. The former shows the operating logic of composite tasks at the subtask level, and the latter shows the specific execution steps of composite tasks at the metatask level. The execution places in the subtask level timed Petri nets can be mapped to metatask timed sub-Petri nets in the metatask level through mapping functions. The hierarchical timed Petri net model uses discrete task scheduling results as input to realize dynamic conflict resolution of discrete task scheduling results during the deduction and simulation process, and is particularly suitable for simulation of discrete event systems such as intelligent manufacturing tasks, intelligent logistics processes, and collaborative control of industrial automation systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to make the purpose, technical solutions and beneficial effects of the present invention more clear, the present invention provides the following drawings for illustration:

[0047] Figure 1 This is a flow chart of the discrete scheduling-oriented hierarchical timed Petri net deduction simulation and conflict resolution method of the present invention;

[0048] Figure 2 This is a schematic diagram of the structure of the hierarchical timed Petri net model;

[0049] Figure 3 A schematic diagram of the structure of the timed Petri net for the subtask hierarchy;

[0050] Figure 4 A schematic diagram of the structure of the meta-task level timed Petri net;

[0051] Figure 5 A schematic diagram of the structure of the timed Petri net for task sequence relations;

[0052] Figure 6 A schematic diagram of the structure of the timed Petri net for task parallel relations;

[0053] Figure 7 A schematic diagram of the structure of the timed Petri net for resource exclusive relations;

[0054] Figure 8 A schematic diagram of the structure of the timed Petri net for resource competition relations;

[0055] Figure 9 Diagram of adjusting step size for resource conflicts. DETAILED DESCRIPTION

[0056] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0057] like Figure 1 As shown, the hierarchical timed Petri net deduction, simulation and conflict resolution method for discrete scheduling in this embodiment includes the following steps.

[0058] Step 1: Construct a hierarchical timed Petri net model

[0059] Obtain the mapping information of composite tasks, subtasks, and metatasks in the scheduling results, as well as the resource usage information of subtasks and metatasks. Use the hierarchical timed Petri net model for discrete tasks to build a hierarchical timed Petri net for the scheduling results. The hierarchical timed Petri net model consists of places, transitions, flow relationships, place delays, transition delays, identifiers, and mapping functions, and includes a subtask hierarchical timed Petri net model and a metatask hierarchical timed Petri net model. The subtask hierarchical timed Petri net model represents the operational logic of composite tasks, while the metatask hierarchical timed Petri net model represents the specific execution steps. The two are linked by the mapping function R, achieving modeling of the hierarchical discrete task operational mechanism from the macro to the micro level.

[0060] like Figure 2 As shown, in this embodiment, the hierarchical timed Petri net model is formally represented by a hierarchical directed graph described by 7-tuples:

[0061] LG=<P,T,F,DP,DT,M,R>

[0062] in:

[0063] P = {PM, PF, PC, PR} is the set of all places in the hierarchical timed Petri net model, including the composite task place set PM, the subtask place set PT, the metatask place set PC and the resource place set PR.

[0064] T = {TF, TC} is the set of all transitions in the hierarchical timed Petri net model, including the subtask transition set TF and the metatask transition set TC.

[0065] F={FF,FC} is the set of all flow relations in the hierarchical timed Petri net model, including the subtask flow relation set FF and the metatask flow relation set FC.

[0066] DP={DPF, DPC} is the delay set associated with the library in the hierarchical timed Petri net model, including the delay set DPF associated with the subtask library and the delay set DPC associated with the metatask library.

[0067] DT={DTF, DTC} is the set of transition-associated delays in the hierarchical timed Petri net model, including the set of delays DTF associated with subtask transitions and the set of delays DTC associated with metatask transitions.

[0068] M={MF,MC} is the set of identifiers of each moment in the hierarchical timed Petri net model, where: MF is a vector describing the number of token values of each resource library in the subtask hierarchical timed Petri net at the current moment; MC is a vector describing the number of token values of each resource library in the metatask hierarchical timed Petri net at the current moment.

[0069] R represents the mapping function of decomposing the subtask execution library into the metatask timed sub-Petri nets in the hierarchical timed Petri net model, and is used to map the subtask execution library into the metatask timed sub-Petri nets.

[0070] like Figure 3 Figure 2 shows the structure of the subtask hierarchical timed Petri net model within the hierarchical timed Petri net model. The subtask hierarchical timed Petri net model consists of composite task places, subtask places, resource places, subtask transitions, flow relationships, and associated delays and place identifiers. Table 1 shows the symbols used in the subtask hierarchical timed Petri net model.

[0071] Table 1 Symbols of the subtask hierarchical timed Petri net model

[0072]

[0073] like Figure 4 Figure 2 shows the structure of the metatask hierarchical timed Petri net model in the hierarchical timed Petri net model. The metatask hierarchical timed Petri net model consists of composite task places, metatask places, resource places, metatask transitions, flow relationships, and associated delays and place identifiers. Table 2 shows the symbols associated with the metatask hierarchical timed Petri net model.

[0074] Table 2 Symbols of the meta-task hierarchical timed Petri net model

[0075]

[0076]

[0077] Both the subtask-level timed Petri net model and the metatask-level timed Petri net model are constructed using four basic Petri nets: sequential, parallel, resource-exclusive, and resource-competition. Specifically, the sequential relationship timed Petri net represents the serial execution logic between tasks; the parallel relationship timed Petri net represents the synchronous execution logic of tasks; the resource-exclusive relationship timed Petri net represents the exclusive resource logic; and the resource-competition relationship timed Petri net represents the resource preemption logic. Therefore, this example will use the subtask-level timed Petri net model as an example to introduce the timed Petri nets corresponding to these four basic relationships one by one.

[0078] like Figure 5 As shown in FIG, the sequential relation timed Petri net in the subtask hierarchy timed Petri net indicates that one subtask occurs after another subtask is completed.

[0079] like Figure 6 As shown in the figure, the parallel relationship timed Petri net in the subtask hierarchy indicates that the execution processes of the two subtasks are carried out independently and in parallel, and will not interfere with each other. However, when one of the subtasks is completed, it must wait for the other subtask to be completed before the subsequent subtask can be executed, thereby achieving synchronization of the two processes.

[0080] like Figure 7 As shown in FIG, the resource exclusive relationship timed Petri net in the subtask level timed Petri net indicates that a certain subtask exclusively occupies a certain resource when it is executed and does not constitute resource competition with other subtasks.

[0081] like Figure 8 The figure shows a timed Petri net for resource competition within a subtask hierarchy. This shows that two or more subtasks compete for a resource during execution, meaning they both occupy the same resource. When a subtask needs to execute but the remaining resource is insufficient, it must wait for other subtasks to complete and release the resource until the remaining resource is reached before it can continue.

[0082] Step 2: Initialize the hierarchical timed Petri net parameters of the scheduling results, including: reading the scheduling results of composite tasks, subtasks and metatasks; initializing the subtask layer delay parameters based on the subtask execution duration and start time; initializing the metatask layer delay parameters based on the metatask execution duration and offset time; initializing the resource library token value according to the resource load upper limit.

[0083] Specifically, in this embodiment, the method steps for initializing the hierarchical timed Petri net parameters of the scheduling result are as follows.

[0084] 21) Read the scheduling results of composite tasks, subtasks and metatasks.

[0085] 22) Obtain the execution duration and start time of each subtask contained in the composite task, and use this information to initialize the delay parameters of the subtask hierarchical timed Petri net model in the hierarchical timed Petri net. The subtask hierarchical delay parameter initialization method is:

[0086]

[0087] Where: dp fd (i,j) is the subtask FE i,j Execution place delay of FE i,j .DT is the subtask FE i,j Execution time of dt fs (i,j) is the subtask FE i,j The start transition delay of FE i,j .ST is the subtask FE i,j The start time of execution.

[0088] 23) Obtain the execution duration and execution offset time of each subtask, and complete the initialization of the delay parameters of the meta-task hierarchical timed Petri net model in the hierarchical timed Petri net. The meta-task hierarchical delay parameter initialization method is:

[0089]

[0090] Where: dp cd (i,j,k) is the meta-task c i,j,k The execution place delay of dt ce (i,j,k) is the meta-task c i,j,k End transition delay; c i,j,k .DT is the meta-task c i,j,k Execution time of c i,j,k .Offset is meta-task c i,j,k The execution offset time of subtask k is FE i,j The number of meta-tasks included; n is the total number of meta-tasks included in the subtask.

[0091] Step 24) Obtain the resource load upper limit used in the scheduling result, and complete the initialization of the token value parameters of the resource library in the hierarchical timed Petri net of the scheduling result.

[0092] Step 3: Execute scheduling result deduction simulation and dynamic conflict resolution, including: calculating the meta-task start time and generating the task list C and time list CST in order from front to back; running the Petri net in chronological order to detect whether the token value of the resource library exceeds the limit; if it exceeds the limit, delay the start time of the conflicting meta-task by a resource conflict adjustment step at, update the task list and re-decode.

[0093] like Figure 9 As shown in Figure 1, the resource conflict adjustment step length at is the amount of time that is added to delay the start time of the later-running meta-task until it coincides with the end time of the earlier-running meta-task that caused the resource conflict, when multiple meta-tasks compete for limited resources simultaneously. In other words, the resource conflict adjustment step length at is defined as the amount of time that is added to delay the start time of the later-running meta-task until it coincides with the end time of the earlier-running meta-task that caused the resource conflict.

[0094] In this embodiment, the method steps for performing scheduling result simulation and dynamic conflict resolution are as follows:

[0095] 31) Using the hierarchical timed Petri net of the initialized scheduling result, calculate the start execution time of the meta-tasks, and generate the meta-task list C and the meta-task start time list CST in order from front to back;

[0096] 32) Let i = 0, t ―1 =min(CST);

[0097] 33) Determine whether i is less than the length of list C: If so, let t i = CST[i], the hierarchical timed Petri net of the running scheduling result, the running step is t = t i ―t i―1 ; If not, go to step 4;

[0098] 34) Determine whether the token value of the resource library occupied by the meta-task C[i] at the current moment exceeds the load limit: if not, set i=i+1 and execute step 33); if so, delay the start execution time of the meta-task by a resource conflict adjustment step at, that is, set CPT[i]=CPT[i]+at, update the meta-task list C and the meta-task start time list CST in the order of the meta-task start execution time from front to back, and execute step 32).

[0099] Step 4: Output the discrete task scheduling results after conflict resolution

[0100] Scheduling results based on hierarchical timed Petri nets are simulated and conflict resolution is completed, and the final execution time of composite tasks, subtasks, and tasks is integrated and output.

[0101] The above embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

Claims

1. A hierarchical timed Petri net deduction, simulation and conflict resolution method for discrete scheduling, characterized by: The steps include: Step 1: Construct a hierarchical timed Petri net model The hierarchical timed Petri net model is composed of places, transitions, flow relations, place delays, transition delays, identifiers, and mapping functions, and includes a subtask hierarchical timed Petri net model and a metatask hierarchical timed Petri net model; the subtask hierarchical timed Petri net model represents the operation logic of the composite task, and the metatask hierarchical timed Petri net model represents the specific execution steps, and the two are associated through a mapping function R; Step 2: Initialize the hierarchical timed Petri net parameters of the scheduling result, including: Read the scheduling results of composite tasks, subtasks, and metatasks; Initialize the subtask level delay parameters based on the subtask execution duration and start time; Initialize meta-task level delay parameters based on meta-task execution duration and offset time; Initialize the resource library token value according to the resource load limit; Step 3: Execute scheduling result simulation and dynamic conflict resolution, including: Calculate the meta-task start time and generate the task list C and time list CST in order from front to back; Run the Petri net in chronological order to detect whether the token value of the resource library exceeds the limit; If the limit is exceeded, the starting time of the conflicting meta-task is postponed by a resource conflict adjustment step at, and the task list is updated and the deduction is repeated; Step 4: Output the discrete task scheduling results after conflict resolution.

2. The hierarchical timed Petri net deduction, simulation and conflict resolution method for discrete scheduling according to claim 1 is characterized by: In the step 1, the hierarchical timed Petri net model consists of 7-tuple LG=<P,T,F,DP,DT,M,R> Formal representation, where: P = {PM, PF, PC, Pr} is a place set, including the composite task place set PM, the subtask place set PF, the metatask place set PC and the resource place set PR; T = {TF, TC} is the transition set, including the subtask transition set TF and the metatask transition set TC; F = {FF, FC} is a flow relationship set, including the subtask flow relationship set FF and the meta-task flow relationship set FC; DP = {DPF, DPC} is the delay set associated with the library, including the delay set DPF associated with the subtask library and the delay set DPC associated with the metatask library; DT = {DTF, DTC} is the set of transition-associated delays, including the set of delays associated with subtask transitions DTF and the set of delays associated with metatask transitions DTC; M = {MF, MC} is a set of identifiers, where MF and MC respectively describe the vectors of the number of token values of each resource library in the subtask level and metatask level timed Petri net models at the current moment; R represents a mapping function, which is used to map the subtask execution library into a meta-task timed sub-Petri net.

3. The hierarchical timed Petri net deduction, simulation and conflict resolution method for discrete scheduling according to claim 1, characterized in that: The subtask hierarchical timed Petri net model consists of compound task places, subtask places, resource places, subtask transitions, flow relations, and associated delays and place identifiers; the metatask hierarchical timed Petri net model consists of compound task places, metatask places, resource places, metatask transitions, flow relations, and associated delays and place identifiers.

4. The hierarchical timed Petri net deduction, simulation and conflict resolution method for discrete scheduling according to claim 1, characterized in that: The subtask hierarchical timed Petri net model and the metatask hierarchical timed Petri net model are both constructed through four basic Petri nets: sequential, parallel, resource exclusive, and resource competition; among them: the sequential relationship timed Petri net represents the serial execution logic between tasks; the parallel relationship timed Petri net represents the task synchronous execution logic; the resource exclusive relationship timed Petri net represents the exclusive resource logic; and the resource competition relationship timed Petri net represents the resource preemption logic.

5. The hierarchical timed Petri net deduction, simulation and conflict resolution method for discrete scheduling according to claim 1, characterized in that: In step 2, the subtask level delay parameter initialization method is: Where: dp fd (i,j) is the subtask FE i,j Execution place delay of FE i,j .DT is the subtask FE i,j Execution time of dt fs (i,j) is the subtask FE i,j The start transition delay of FE i,j .ST is the subtask FE i,j The start time of execution.

6. The hierarchical timed Petri net deduction, simulation and conflict resolution method for discrete scheduling according to claim 1, characterized in that: In the step 2, the method for initializing the meta-task level delay parameters is: Where: dp cd (i,j,k) is the meta-task c i,j,k The execution place delay of dt ce (i,j,k) is the meta-task c i,j,k End transition delay; c i,j,k .DT is the meta-task c i,j,k Execution time of c i,j,k .Offset is meta-task c i,j,k The execution offset time of subtask k is FE i,j\ The number of meta-tasks included; n is the total number of meta-tasks included in the subtask.

7. The hierarchical timed Petri net deduction, simulation and conflict resolution method for discrete scheduling according to claim 1, characterized in that: In step 3, the resource conflict adjustment step length at is defined as: delaying the start time of the later-executed meta-task to a time that coincides with the end time of the earlier-executed meta-task that caused the resource conflict.

8. The hierarchical timed Petri net deduction, simulation and conflict resolution method for discrete scheduling according to claim 1, characterized in that: In step 3, the method steps for performing scheduling result simulation and dynamic conflict resolution are as follows: 31) Using the hierarchical timed Petri net of the initialized scheduling result, calculate the start execution time of the meta-tasks, and generate the meta-task list C and the meta-task start time list CST in order from front to back; 32) Let i = 0, t ―1 =min(CST); 33) Determine whether i is less than the length of list C: If so, let t i = CST[i], the hierarchical timed Petri net of the running scheduling result, the running step is t = t i ―t i―1 ; If not, go to step 4; 34) Determine whether the token value of the resource library occupied by the meta-task C[i] at the current moment exceeds the load limit: if not, set i=i+1 and execute step 33); if so, delay the start execution time of the meta-task by a resource conflict adjustment step at, update the meta-task list C and the meta-task start time list CST in the order of the meta-task start execution time from front to back, and execute step 32).

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